Culture secretary Jeremy Hunt has asked Ofcom to look at how media plurality should be measured and whether it is possible to set limits on media ownership to protect plurality.

The issue came to the fore when critics argued that News Corp's proposed £8bn takeover of Sky raised long-term plurality concerns – because the satellite broadcaster's growth would further increase News Corp's UK dominance – but that existing laws only allowed for a review when a merger situation arose.

Ed Richards, the chief executive of Ofcom, has previously called for the ability to review plurality on the basis of factors such as a media organisation's growth or "a change in audience levels or viewing share".

Ofcom on Friday called for comments from interested parties on a range of questions including:

• What are the options for measuring media plurality across platforms? What do you recommend is the best approach?

• Is it practical or advisable to set absolute limits on news market share?

• What could trigger a review of plurality in the absence of a merger, how might this be monitored and by whom?

• Could or should a framework for measuring levels of plurality include websites, and if so which ones?

• Whether or how it should include the BBC.

Written submissions are due by 17 November.

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